摘要
本文用LMTO-ASA能带技术结合新的虚晶近似处理方法和冻结声子模型,计算了三元合金Ga_(1-x)Al_xAsΓ点的光学声子形变势(ODP)do及v轴上ODP的d_(30),d_(10)(val)和d_(10)(cond),预言了它们作为Al组分x的函数关系,发现这些ODP都可用x的二次方程表示,其中d_0随x增加而减小的弯曲参数很小,是近乎线性的,理论预言了x≈0.65处d_(10)(val)=d_(10)(cond),因而d_(30)/d_(10)比值在此组分下发散。表明在此组分下,Ga_(1-x)Al_xAs体系的二带项对E_1—E_1+△_1能隙的一级共振Raman散射的贡献可以被忽略。
The optical-phonon deformation potentials (ODP's) of the tranary compounds Ga1-xAlxAs have been calculated by LMTO-ASA band structure technique combining with a virtual crystal approximation and a frozen-phonon model. The ODP's as a function of the Al composition x has been predicted. We find that the ODP's d0,d30,d10(val)and d10(cond) can be expressed as a quadratic equation of the compositions. Among them a small bending parameter is only connected with the do vs x, showing it to be a nearly linear dependence. The computational results also show that the d10(val) will equal to the d10(cond) at x≈0.65. So the ratio d30/d10 should be divergent at that composition. This fact implies that the contribution of the two-band term to the Raman tensor of the first-order resonance Raman scattering for energy gap E1-E1+△1 can be neglected at that composition in Ga1-xAlxAs. The reliability of our calculation results has been verified by using the relationship between the ODP's.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
1990年第11期1778-1784,共7页
Acta Physica Sinica
基金
国家自然科学基金资助的课题
福建省自然科学基金资助的课题
